Israeli officials also said Israeli forces were preparing to cede some of their positions in south Lebanon to UN peacekeepers and withdraw more troops on Wednesday.

The officials said the move was for the UN force, known as the UNIFIL, to deploy soldiers on Wednesday and Thursday, in some of the Israeli positions.

Meanwhile, the Lebanese army was expected to start deploying forces to the Litani River and then slowly move southward as the Israeli army pulls back.

The truce to end the five-week-old fighting between Israel and Lebanon's Hezbollah began Monday and has fared well so far.

But new casualties occurred as Israeli troops killed at least one Hezbollah guerrilla on Monday after the truce. Israel said Hezbollah fighters had also fired mortars since the truce began, but the firing caused no casualties.

The truce was agreed after the UN Security Council adopted a resolution last Friday to end the Israel-Hezbollah hostilities, which have killed at least 1,110 people in Lebanon and 157 in Israel, and left about 200,000 Lebanese displaced.

As required by the Council resolution, a senior Lebanese official said his country will begin moving 15,000 troops south of the Litani River on Thursday.

The Lebanese forces would stay out of areas occupied by Israeli troops until UN peacekeepers move in, the source said.

Under the UN resolution, an expanded UNIFIL force will move into southern Lebanon with existing Lebanese troops, as Israel withdraws.

Discussions on the enlarged UN force were still under way with potential contributing nations planning to hold a second meeting on Thursday to agree on a "concept of operations."

The UN expects that a vanguard contingent of 3,500 international troops will be deployed to southern Lebanon within two weeks, a senior UN official said on Tuesday.

"We would like to see 3,000 to 3,500 troops within 10 days to two weeks," said Hedi Annabi, the assistant secretary-general for UN peacekeeping operations.

The advance team will help consolidate the cessation of hostilities and start the process of the Israeli withdrawal and deployment of the Lebanese forces, Annabi told reporters at the UNheadquarters.

No timetable has been set for the deployment of the force, saidAnnabi, adding that it depends on how the contributing countries would respond to a call for their contribution.

UN Secretary-General Kofi Annan said Monday that he had not yet received firm commitments from countries which have said they may contribute troops to the enhanced UN peacekeeping force.

UN spokesman Stephane Dujarric told reporters on Tuesday that no formal offers had yet been received but the United Nations continued holding technical meetings with military advisors from member states.

He added that 17 member states attended a meeting on Monday and 28 attended a meeting on Saturday.

"We hope to have a more formal meeting with the potential troop contributors on Thursday," Dujarric said. "We do expect a more formal meeting on Thursday at which point hopefully we will get those offers."

France, Spain, Italy and some other countries had announced they would participate in the reinforced UNIFIL.

A senior UN official told journalists that much depended on whether France would contribute a significant number of troops and become the backbone of the force.

French Foreign Minister Philippe Douste-Blazy will head for Beirut on Wednesday to discuss the force's deployment, the reopening of Lebanon's ports and airport, and humanitarian aid, France's Foreign Ministry said.

But the United States said on Tuesday it would not take part inthe UN peacekeeping force in Lebanon.

"We ourselves are not going to be actually deploying as part" of the UNIFIL, State Department spokesman Sean McCormack told a news briefing on Tuesday.

He said the U.S. had experience in the logistics and deployment planning for these kinds of forces, and would take part in the planning process.